Translation is the communication of the meaning of a source-language text by means of an equivalent target-language text. The English language draws a terminological distinction (not all languages do) between translating (a written text) and interpreting (oral or sign-language communication between users of different languages); under this distinction, translation can begin only after the appearance of writing within a language community.
Shallow lakes have been greatly affected by increased concentrations of nitrogen and phosphorus from intensive agriculture and increased human populations. These key nutrients for plant growth enter the aquatic environment, changing clear water to turbid through a phenomenon called eutrophication.